Conventionally, there has been known an image reading apparatus which is mounted on a copying apparatus, a scanner apparatus or a multi function apparatus having a copy function and a scanner function and comprises an automatic document delivering device referred to as an ADF (Auto Document Feeder) for delivering a document from a sheet feed tray to a sheet discharge tray through a delivery path. Moreover, there has been known an image reading apparatus for switching back a document having both sides, that is, first and second faces which are printed, in the middle of a delivery to invert a leading and a trailing end in the document, thereby reading both sides of the document in order to read the document (see JP-A-7-64359)
On the other hand, there has been known an image reading apparatus capable of reading an image of another document during an image reading operation which is being carried out as in an interruption copy in a copying apparatus. In such an image reading apparatus, reading conditions for the image reading operation carried out partway and image data are stored in a predetermined region of a memory in the interruption copy, and the interrupted image reading operation is restarted by using the reading conditions and the image data which are stored in the memory after the interruption copy is ended so that the interruption copy is implemented without wasting the image reading operation carried out partway (see JP-A-5-199341).
In the case in which a first image reading operation is interrupted and a second image reading operation is then carried out in the image reading apparatus as in the interruption copy, it is necessary to replace a document subjected to the first image reading operation partway with a document over which the second image reading operation is to be carried out. In other words, the first image reading operation is interrupted and a current document is then removed from a sheet feed tray and a sheet discharge tray of the image reading apparatus, and another document over which the second image reading operation is to be carried out is set onto the sheet feed tray. When the second image reading operation is ended, thereafter, the read document is removed from the sheet discharge tray and the document subjected to the first image reading operation partway is set onto the sheet feed tray again. Subsequently, the first image reading operation is restarted.
The interruption copy is used for an urgent copy, and furthermore, is also used for preventing another person from waiting for a copy of one document for a long time in the case in which a copying apparatus is occupied for a long period of time in order to read images of a large number of documents, for example. However, a work for removing a large number of documents from the sheet feed tray and the sheet discharge tray to execute the interruption copy and setting the documents again after the end of the interruption copy is also complicated.